title: Direct observation of size fractionation during colloidal crystallization.
abstract: We present a confocal microscopy study of the quasi-two-dimensional crystallization of a binary mixture of spherical colloids coated with long DNA strands. Our experiments show that in the crystalline phase the two colloidal species are completely demixed. Analysis of the lattice spacings in the two types of colloidal crystal shows that the diameters of the two species of colloids differ by 10%. We argue that the demixing in the crystalline phase is due to size segregation during crystallization. This phenomenon had been predicted in several theoretical studies. To our knowledge, the present study provides the first 'real-space' experimental confirmation of this effect.
authors.affiliation: FOM Institute for Atomic and Molecular Physics (AMOLF), Science Park 104, 1098XG Amsterdam, The Netherlands.
authors.forename: Nienke
authors.initials: N
authors.lastname: Geerts
authors.forename: Sabrina
authors.initials: S
authors.lastname: Jahn
authors.forename: Erika
authors.initials: E
authors.lastname: Eiser
mesh_terms: D000465:Algorithms; D001703:Biophysics / Q000379:methods*; D002021:Buffers; D003102:Colloids / Q000737:chemistry*; D003198:Computer Simulation; D003460:Crystallization; D004247:DNA / Q000737:chemistry*; D019344:Lactic Acid / Q000737:chemistry; D018613:Microscopy, Confocal / Q000379:methods*; D015233:Models, Statistical; D008968:Molecular Conformation; D010316:Particle Size; D011091:Polyesters; D011092:Polyethylene Glycols / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D013395:Sucrose / Q000737:chemistry; D013997:Time Factors
chemical_list: D002021:Buffers; D003102:Colloids; D011091:Polyesters; D011108:Polymers; D019344:Lactic Acid; D011092:Polyethylene Glycols; C033616:poly(lactide); D013395:Sucrose; D004247:DNA